不同电价下含储能系统的微电网经济调度

为了验证不同电价下储能技术的削峰填谷及其在电力系统经济调度中的作用,对含有储能的微电网进行建模分析。建立了含有风机、光伏电池、热电联产系统、燃料电池、燃气锅炉及储能系统的并网型微电网结构,在充分考虑电力市场分时/实时电价的条件下,优化了计及设备维护成本、售热收益和微电网与大电网之间的电能交互成本等的经济模型,并采用混合杂草蝙蝠算法对所提模型进行了优化。以2种电价下不含储能系统的微电网经济调度模型作为对照,通过具体的微电网实例优化了冬季典型日负荷下各微电源的最优机组出力和最佳运行成本。仿真结果验证了所提算法和模型的有效性：储能能够在电价引导下对网内电负荷削峰填谷并降低微电网运行成本;同时,不同电价政策对微电网总运行成本及储能作用的发挥影响不同。     

编组站自编始发货物列车定点发车模式的适应性研究

在对发车模式作了一定假设的前提下,通过对货物列车编发及运行的相关收益和损失的分析,给出了定点发车模式中最小编成辆数的理论计算公式;根据这个公式给出了最小编成辆数与列车在区段上的运行时间以及车流量大小之间的变化规律,并通过仿真的方法验证了理论分析的正确性.     

金融危机下解决就业问题的现实出路

当前国际金融危机还在继续蔓延,对我国实体经济的冲击风险将有所扩展,导致我国的就业形势面临前所未有的挑战。目前看来,有两大群体的就业形势较为严峻。笔者认为从全力普及以市场就业为导向的职业教育和技能培训这个层面去探索,无疑是当前解决就业问题的现实出路所在。     

基于有限状态机的按键检测

介绍了一种C51下的按键检测方式,并给出了程序的运行方法。     

基于Spring Security ACL的系统访问控制研究

Spring Security ACL是一个权限访问控制框架,主要用来控制各种资源的访问权限。本文讲述Spring Security ACL的机制原理和理论研究,同时也通过一个简单的权限控制实现的例子演示Spring Security ACL的安全框架的实现方法和过程。     

杂多酸催化法制备低摩尔质量羟基封端氟硅油

采用杂多酸催化1,3,5-三(3’,3’,3’-三氟丙基)-1,3,5-三甲基环三硅氧烷的开环聚合反应,分别合成了低摩尔质量的羟基封端三氟丙基硅油、羟基封端三氟丙基甲基-二甲基硅油、羟基封端三氟丙基甲基-乙烯基甲基硅油。对3种羟基封端氟硅油的结构进行了表征,讨论了氟硅油的摩尔质量与黏度的关系。通过1H NMR谱图计算出3种氟硅油的平均摩尔质量分别为642、613、657 g/mol,黏度分别为0.16、0.12和0.08 Pa.s。即在相近摩尔质量的情况下,三氟丙基的含量直接影响了氟硅油的黏度,同时甲基与乙烯基空间结构的不同也对氟硅油的黏度产生一定影响。     

β-TCP scaffold coated with PCL as biodegradable materials for dental applications

Requirements for an ideal scaffold include biocompatibility, biodegradability, mechanical strength and sufficient porosity and pore dimensions. Beta tricalcium phosphate (β-TCP) has competent biocompatibility and biodegradability, but has low mechanical strength because of its porous structure. Polycaprolactone (PCL) is a biodegradable polymer with elastic characteristics and good biocompatibility. In this study, β-TCP/PCL composites were prepared in different ratio and their morphology, phase content, mechanical properties, biodegradation and biocompatibility were investigated. After coating, surfaces of β-TCP scaffolds were covered with the PCL while some of the pores were partially clogged. The compression and bending strength of β-TCP scaffolds were significantly enhanced by PCL coating. The degradation rate of the scaffold in Tris buffer was reduced with higher content of the PCL coating. MTT and ALP assays showed that the osteoblast cells could proliferate and differentiate on PCL coated scaffolds as well as on bare β-TCP scaffolds. Based on the comprehensive analysis achieved in this study, it is concluded that the β-TCP/PCL composite scaffold fabricated with 40% β-TCP and 5% PCL exhibits optimum properties suitable for dental applications.     

载重子午线轮胎温度变化的影响因素分析

利用红外线测温仪及探针式热电偶，对5个不同规格的载重子午线轮胎表面及内部温度进行测试，并应用多元线性回归方法建立轮胎温度与行驶速度、负荷、充气压力和环境温度等多因素变化之间的关系。结果表明：轮胎温度随着行驶速度的提高小幅升高；负荷是影响轮胎温度变化的重要因素；充气压力过低会造成轮胎过度生热；当环境温度升高到一定程度后，轮胎表面的热量传至环境的能力降低，使轮胎内部温度升高。     

Impact of support oxide and Ba loading on the NOx storage properties of Pt/Ba/support catalysts: CO2 and H2O effects

A series of 1 wt.%Pt/_xBa/Support (Support = Al₂O₃, SiO₂, Al₂O₃-5.5 wt.%SiO₂ and Ce_0.7Zr_0.3O₂, x = 5–30 wt.% BaO) catalysts was investigated regarding the influence of the support oxide on Ba properties for the rapid NO_x trapping (100 s). Catalysts were treated at 700 °C under wet oxidizing atmosphere. The nature of the support oxide and the Ba loading influenced the Pt–Ba proximity, the Ba dispersion and then the surface basicity of the catalysts estimated by CO₂-TPD. At high temperature (400 °C) in the absence of CO₂ and H₂O, the NO_x storage capacity increased with the catalyst basicity: Pt/20Ba/Si < Pt/20Ba/Al5.5Si < Pt/10Ba/Al < Pt/5Ba/CeZr < Pt/30Ba/Al5.5Si < Pt/20Ba/Al < Pt/10BaCeZr. Addition of CO₂ decreased catalyst performances. The inhibiting effect of CO₂ on the NO_x uptake increased generally with both the catalyst basicity and the storage temperature. Water negatively affected the NO_x storage capacity, this effect being higher on alumina containing catalysts than on ceria–zirconia samples. When both CO₂ and H₂O were present in the inlet gas, a cumulative effect was observed at low temperatures (200 °C and 300 °C) whereas mainly CO₂ was responsible for the loss of NO_x storage capacity at 400 °C. Finally, under realistic conditions (H₂O and CO₂) the Pt/20Ba/Al5.5Si catalyst showed the best performances for the rapid NO_x uptake in the 200–400 °C temperature range. It resulted mainly from: (i) enhanced dispersions of platinum and barium on the alumina–silica support, (ii) a high Pt–Ba proximity and (iii) a low basicity of the catalyst which limits the CO₂ competition for the storage sites.     

谈外保温墙面产生质量问题的原因及对策

对外保温墙面常见质量问题发生的原因从设计、环境、材料、施工等方面进行分析,有针对性的提出解决措施,以期彻底解决外保温墙面的质量问题。